Nd11Fe71Co8V1.5Cr1B7.5合金结构与磁性能的研究

采用熔体快淬及晶化处理工艺制备Nd11Fe71Co8V1.5Cr1B7.5纳米晶合金. 运用XRD, DTA等方法研究了快淬工艺与热处理工艺对该合金纳米晶形成、晶化过程及磁性能的影响. 结果表明, 快淬速度和热处理温度都明显地影响Nd11Fe71Co8V1.5Cr1B7.5纳米晶的形成及其磁性能; 该合金在晶化过程中先后出现了3个放热峰, 分别对应软磁相α-Fe, 亚稳相和硬磁相Nd2Fe14B 3个晶化相. 快淬速度21 m*s-1制备快淬薄片经640 ℃/4 min晶化处理后, 制成的粘结磁体的最佳磁性能为 Br=0.64 T, JHc=903.5 kA·m-1, (BH)max=71 kJ·m-3.     

影响压延取向粘结磁体性能的因素

从分析压延取向对粘结磁体矫顽力等的机制入手,通过扫描电镜、图象仪等工龄研究了影响磁粉形貌及磁体性能的因素,结果表明：磁粉颗粒的径厚比（D／H）是影响磁体性能的关键因素,合适的径厚比能使 粉在取向过程中获得最大有效的取向力矩,同时又能使该应力所引起的晶格畸变最小,获得综合性能优越的磁体;还他磁粉预烧温度、混料方式、预烧助溶剂以及磁体压延取向工艺的混炼温度对磁体性能的影响,为制造磁粉和磁体提供工艺依据。     

快淬NdFeB磁粉的磁选分离

快淬NdFeB磁粉的制备过程中有许多因素影响磁粉性能的均匀性 ,致使出现部分低性能的磁粉 ,磁选可把低性能的磁粉分离出来。研究了磁选时辊轮转速、磁选次数以及磁场强度对快淬Nd9.5(FeCoZrAl) 84 .5B6 磁粉分离效果的影响。研究表明 ,选择合适的磁选工艺参数能有效分离低矫顽力的磁粉。与未磁选的Nd9.5(FeCoZrAl) 84 .5B6 磁粉制作的粘结磁体相比 ,磁选后的磁粉制作的粘结磁体磁性能有较大的提高 ,最佳磁性能为 :Br=697.4mT ,Hcb=44 2kA·m- 1 ,Hcj=741kA·m- 1 ,(BH) max=77kJ·m- 3。     

Recycle for Sludge Scrap of Nd-Fe-B Sintered Magnet as Isotropic Bonded Magnet

The reduction diffusion method was performed for the sludge scrap of Nd-Fe-B sintered magnets with adding Ca metal to recover the oxidized Nd-Fe-B phase. After washing the resultant powders to remove Ca metal component, the powders obtained were recycled as an isotropic magnetic powder by the melt spinning method. The magnetic properties of powders as recycled were inferior, especially for the coercivity value, due to the deletion of rare earth metals during the washing process. The adjustment of metal composition, i.e., the addition of Nd metal, at the melt spinning process improved the magnetic properties to be Br=～0.75 T, Hcj=～0.93 mA·m-1, and(BH)max=～91 kJ·m-3. The magnetic properties of the bonded magnets prepared from the composition-adjusted powders were Br=～0.66 T, Hcj=～0.92 mA·m-1, and(BH)max=～70 kJ·m-3, which are approximately comparable to the commercially available MQPB boned one(Br=～0.73 T, Hcj=～0.79 mA·m-1, and(BH)max=～86 kJ·m-3).     

磁粉及其偶联处理对压延取向橡胶粘结磁体性能的影响

通过对压延取向橡胶粘结磁体的磁性能及力学性能的测量和在扫描电镜上对磁粉颗粒形貌及粘结磁体拉伸断口形貌的观察研究，表明同样条件下，磁粉径厚比分布合理是保证粘结磁体性能的关键。磁粉大小均匀，径厚比大约在3．0～4．0之间时，磁体综合性能良好；偶联剂的种类及偶联处理工艺也对磁体性能有重要影响。     

不同粘结剂对粘结NdFeB磁体磁性能和抗压强度的影响

本文采用三种不同环氧值的粘结剂制备了NdFeB粘结磁体,研究了粘结剂环氧值影响磁体磁性能及抗压强度的规律及其机理.实验结果表明,在优化的固化工艺条件下,采用环氧值适中的环氧树脂制备的磁体,具有较好的磁性能和抗压强度.     

工艺参数对注射成形各向异性粘结NdFeB磁体性能的影响

研究了注射温度、模具温度、注射压力及注射速度对注射成形各向异性粘结NdFeB磁体的磁性能及力学性能的影响，并分析了其原因。结果表明：注射温度及模具温度对磁体磁性能影响较大，而注射压力则对磁体的抗压强度影响较大。在最佳的注射参数下，获得了最大磁能积和抗压强度分别为90kJ／m^3及130MPa的高性能粘结磁体。     

HDD法粘结NdFeB磁体的磁性能

研究了NdFeB合金成分、均匀化处理和HDD处理脱氢过程对磁性粉末及粘结磁体磁性能的影响。实验表明,HDD法制备的NdFeB粉末具有较好的温度稳定性和时间稳定性。     

Nd_(11)Fe_(71)Co_8V_(1.5)Cr_1B_(7.5)合金结构与磁性能的研究

采用熔体快淬及晶化处理工艺制备Nd1 1 Fe71 Co8V1 .5Cr1 B7.5纳米晶合金。运用XRD ,DTA等方法研究了快淬工艺与热处理工艺对该合金纳米晶形成、晶化过程及磁性能的影响。结果表明 ,快淬速度和热处理温度都明显地影响Nd1 1 Fe71 Co8V1 .5Cr1 B7.5纳米晶的形成及其磁性能 ;该合金在晶化过程中先后出现了 3个放热峰 ,分别对应软磁相α Fe ,亚稳相和硬磁相Nd2 Fe1 4B 3个晶化相。快淬速度 2 1m·s- 1 制备快淬薄片经 64 0℃ 4min晶化处理后 ,制成的粘结磁体的最佳磁性能为 :Br=0 64T ,JHc=90 3 5kA·m- 1 ,(BH) max=71kJ·m- 3。     

注射成形钕铁硼粘结磁体研究的现状及前景

论述了注射成形钕铁硼粘结磁体的特点及发展趋势，分析了其生产工艺中的四个关键因素。包括磁粉，粘结剂与耦联剂，注射过程，充磁过程，并对这四个关键因素的研究状况作了综合评述，认为今后对注射成形钕铁硼粘结磁体的研究开发将集中在四个主要的方面。     

粉末粒度对注射粘结磁体性能的影响

实验分析了粉末粒度对制得的注射粘结磁体密度、取向度和磁性能的影响,得出了磁粉粒径太大和太小均不利于磁体磁性能的提高的结论．同时,通过搭配不同比例的粉末,可以提高磁体的装载量,从而达到提高磁性能的目的．     

注射成形粘结钕铁硼磁体复合粉研究

磁体的注射成形是一种高效生产的近净成形技术。为了制备出具有较好综合性能的注射成形粘结钕铁硼永磁材料,研究了粘结剂对注射成形磁体的磁性能、加工性能及力学性能的影响;分析了硅烷系列的偶联剂、复合润滑剂和抗氧剂等添加剂对注射成形磁体性能的影响。结果表明,用MQP-B快淬钕铁硼磁粉和尼龙12粘结剂制备出了剩余磁感应强度为0.539 T,磁感矫顽力为345.37 k A/m,内禀矫顽力为681.02 k A/m,最大磁能积为47.37 k J/m3的注射成形钕铁硼磁体。     

注射成形钕铁硼粘结磁体研究的现状及前景

论述了注射成形钕铁硼粘结磁体的特点及发展趋势,分析了其生产工艺中的4个关键因素,包括磁粉、粘结剂与藕联剂、注射过程、充磁过程,并对这4个关键因素的研究状况作了综合评述,认为今后注射成形钕铁硼粘结磁体的研究开发将主要集中在以下4个方面研究:各向异性粉末和各向异性粘结磁体,研发合适的粘结体系及注射成形工艺参数,开发磁能积更高的磁体,开发耐热钕铁硼粘结磁体。     

硫化剂对CPE粘结磁体性能的影响

针对高填充率的氯化聚乙烯(CPE)粘结磁体，提供几种常用的硫化体系．通过分析硫化体系的硫化特性，找出不同的硫化体系对磁体性能的影响．     

Magnetic properties and magnetization mechanism of anisotropic NdFeB/SmFeN hybrid bonded magnets prepared with different coercivity NdFeB powders

Anisotropic NdFeB/SmFeN hybrid bonded magnets were prepared by warm compaction process under an orientation magnetic field of 22 kOe,mixing with anisotropic SmFeN powders in different addition and HDDR-NdFeB powders in different coercivity.With the addition of 20 wt% SmFeN,the density and remanence of hybrid magnets increase from 5.58 g/cm³,8.4 kGs to 6.02 g/cm³,9.0 kGs,respectively.And as the addition amount of SmFeN powders varies from 20 wt% to 40 wt%,the maximum energy ...     

Nd2Fe14B/Fe3B基纳米复合粘结磁体的磁特性

通过实验研究了Nd2Fe14B／Fe3B双相纳米复合磁粉分别与几种不同性能的磁粉复合成粘结磁体后磁性能的变化。通过对复合磁体的理论分析得知，由Nd2Fe14B／Fe3B与RE2Fe14B或铁氧体磁粉复合成的粘结磁体中，成分间并未发生化学反应。以Nd2Fe14B／Fe3B铁氧体复合粘结磁体为例，根据理论分析推出的剩磁Br-成分含量关系曲线与实际曲线吻合得很好，表明剩磁与成分含量间存在着近似的线性关系，从而可通过数学手段建立磁性能参数与成分含量的函数关系式，用于简化混粉工艺。另外，添加铁氧体可对该复合磁体较差的热稳定性起到补偿作用，并减少了磁不可逆损失。     

Preparation and characterization of sodium silicate/epoxy resin composite bonded Nd-Fe-B magnets with high performance

As an organic binder for bonded Nd-Fe-B magnets, epoxy resin(EP) has poor heat resistance but good moisture resistance, while sodium silicate(SS) has poor moisture absorption but better heat resistance and corrosion resistance. In order to improve high temperature stability and decrease moisture absorption of bonded Nd-Fe-B magnets, EP/SS composites were applied as the binder to prepare bonded Nd-Fe-B magnets. The magnetic properties, moisture absorption, corrosion resistance, compressive strength and microstructure of composite bonded magnets were investigated. The results show that EP/SS bonded magnets can obtain excellent magnetic properties at room temperature, and even useable magnetic properties a thigh temperature environments at 200°C. EP/SS composite binder effectively improves heat resistance and corrosion resistance of bonded Nd-Fe-B magnets, and reduces the hygroscopic properties. The molecule of sodium silicateis rigid and keeps it original shape at high temperature environments. In addition, SS in composite binder improves the mobility of the magnetic powders during the pre-pressing process, which makes the magnetic powders attain a more regular structure. These two factors will increase the mechanical properties. Moreover, sodium silicate in the composite binder can also cover the surfaces protecting the magnetic powders from oxidation and corrosion. EP in composite binder can cover SS surface to reduce the water absorption of SS as epoxy is a hydrophobic material. The EDX analysis shows that the composite binder has accumulated in the gaps of the magnet powders, which not only improves heat resistance and corrosion resistance, but also increases the mechanical properties. Therefore, EP/SS composite binder endows bonded Nd-Fe-B magnets excellent comprehensive properties.